CDT CDT Complete Denture Fabrication 1 — Questions and Answers
Question 1: What is the purpose of a custom tray in complete denture fabrication?
- To provide a reusable stock impression tray for efficiency
- To create a close-fitting tray that produces a more accurate final impression (Correct answer)
- To record jaw relation records
- To serve as the final denture base
Correct answer: To create a close-fitting tray that produces a more accurate final impression
A custom tray is fabricated to the individual patient's ridge, enabling a uniform thickness of impression material and more accurate final impression.
Question 2: What does 'freeway space' (interocclusal distance) refer to in complete denture prosthodontics?
- The distance between the maxillary and mandibular ridges at maximum intercuspation
- The space between the posterior teeth when the patient is at rest, minus the occlusal vertical dimension (Correct answer)
- The lateral distance between the denture flanges
- The clearance between the denture base and the palate
Correct answer: The space between the posterior teeth when the patient is at rest, minus the occlusal vertical dimension
Freeway space is the difference between the rest vertical dimension and the occlusal vertical dimension, typically 2–4 mm in complete denture patients.
Question 3: What is the primary function of a wax occlusal rim (bite rim) during complete denture fabrication?
- To serve as the final occlusal surface of the denture
- To record vertical dimension, centric relation, and lip support for tooth arrangement (Correct answer)
- To act as a spacer for the impression material
- To test the fit of the denture base before processing
Correct answer: To record vertical dimension, centric relation, and lip support for tooth arrangement
Occlusal rims allow the dentist to record jaw relationship records and establish the correct vertical dimension and anterior tooth position.
Question 4: What articulator movement is recorded by a facebow transfer?
- Lateral excursive movements
- Protrusive movements
- The spatial relationship of the maxillary arch to the temporomandibular joints (Correct answer)
- The centric occlusion record
Correct answer: The spatial relationship of the maxillary arch to the temporomandibular joints
A facebow records the position of the maxillary arch relative to the hinge axis of the TMJ so the articulator mimics the patient's jaw movements.
Question 5: Which factor most commonly causes a complete denture to lose retention over time?
- Polishing the denture base too smoothly
- Residual ridge resorption reducing the tissue-bearing area (Correct answer)
- Using acrylic teeth instead of porcelain
- Over-extension of the lingual flange
Correct answer: Residual ridge resorption reducing the tissue-bearing area
Progressive bone resorption under the denture reduces the intimate contact between the denture base and the tissue, reducing suction and retention.
Question 6: What is 'centric relation' in the context of complete denture fabrication?
- The position of maximum intercuspation of the denture teeth
- The most retruded, unstrained position of the mandibular condyles in the fossae (Correct answer)
- The rest position of the mandible
- The position recorded when the patient swallows
Correct answer: The most retruded, unstrained position of the mandibular condyles in the fossae
Centric relation is a reproducible, bone-supported jaw position used to set complete denture teeth when no natural teeth guide occlusion.
CDT CDT Complete Denture Fabrication 1
What is the purpose of a custom tray in complete denture fabrication?